861 research outputs found

    Dinâmica populacional de Pseudococcidae (hemiptera) em videiras no Vale do São Francisco.

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    O objetivo do trabalho foi estudar a dinâmica de cochonilhas farinhentas em videiras de diferentes áreas de cultivo em Petrolina-PE

    INVESTIGAÇÃO FITOQUÍMICA E AVALIAÇÃO DA ATIVIDADE ANTIBACTERIANA DA Mikania lanuginosa DC (ASTERACEAE)

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    O presente trabalho envolveu extração, isolamento, purificação e identificação dos constituintes químicos das partes aéreas da Mikania lanuginosa DC (ASTERACEAE). No processo de extração ocorreu a formação de um precipitado, no qual foi isolado e purificado um composto majoritário, que por análises espectroscópicas de IV, RMN 1H, RMN 13C e por comparação com os dados existentes na literatura, foi identificado como sendo o diterpeno ácido caurenóico. Foram realizados ensaios biológicos para avaliar a ação antimicrobiana com o precipitado, extrato etanólico bruto, as frações hexânica, diclorometano, acetato de etila, butanólica e o diterpeno ácido caurenóico contra as cepas Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228 e Bacillus cereus, pela técnica da difusão em meio sólido por cavidade e posteriormente pelo método de diluição em placa. Os resultados demonstraram que as frações hexânica, diclorometano, acetato de etila, butanólica e o ácido caurenóico obtidos da M. lanuginosa, apresentaram atividade antimicrobiana moderada frente as bactérias Gram positivas e foram inativos contra as bactérias Gram negativas. Phytochemical Investigation and Antimicrobial Activity Evaluation of the Mikania lanuginosa DC (ASTERACEAE) Abstract The present study investigated the extraction, isolation and purification the chemical compounds of the aerial parts of Mikania lanuginosa DC (ASTERACEAE). In the process of extraction it occurred the formation of a precipitate, it which was isolated and purified a ruling compound, and by spectroscopic analysis of the IR, 1H NMR, 13C NMR and comparison with reported data in the literature it was identified as being the diterpene kaurenoic acid. It were performed biological assays to estimate the antimicrobial action with the precipited, crude etanolic extract, hexane, dichoromethane, acetate ethyl, butane fractions and diterpene kaurenoic acid contrasting with strains Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228 e Bacillus cereus, by technique of the diffusion in solid mean by cavity and afterwards by the plaque dilution method. The results showed that the hexane, dichoromethane, acetate ethyl, butane fractions and the kaurenoic acid obtained from the Mikania lanuginosa DC presented a moderate antimicrobial activity face to Gram positives bacteria and got inert against the Gram negatives bacteria

    Covariant and Heavy Quark Symmetric Quark Models

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    There exist relativistic quark models (potential or MIT-bag) which satisfy the heavy quark symmetry (HQS) relations among meson decay constants and form factors. Covariant construction of the momentum eigenstates, developed here, can correct for spurious center-of-mass motion contributions.Proton form factor and M1 transitions in quarkonia are calculated. Explicit expression for the Isgur-Wise function is found and model determined deviations from HQS are studied. All results depend on the model parameters only. No additional ad hoc assumptions are needed.Comment: 34 pages (2 figures not included but avaliable upon request), LATEX, (to be published in Phys.Rev.D

    Neutron cross-sections for advanced nuclear systems : The n-TOF project at CERN

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    © Owned by the authors, published by EDP Sciences, 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n-TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.Peer reviewedFinal Published versio

    Olfactory perireceptor and receptor events in moths: a kinetic model revised

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    Modelling reveals that within about 3 ms after entering the sensillum lymph, 17% of total pheromone is enzymatically degraded while 83% is bound to the pheromone-binding protein (PBP) and thereby largely protected from enzymatic degradation. The latter proceeds within minutes, 20,000-fold more slowly than with the free pheromone. In vivo the complex pheromone–PBP interacts with the receptor molecule. At weak stimulation the half-life of the active complex is 0.8 s due to the postulated pheromone deactivation. Most likely this process is enzymatically catalysed; it changes the PBP into a scavenger form, possibly by interference with the C-terminus. The indirectly determined PBP concentration (3.8 mM) is close to direct measurements. The calculated density of receptor molecules within the plasma membrane of the receptor neuron reaches up to 6,000 units per μm2. This is compared with the estimated densities of the sensory-neuron membrane protein and of ion channels. The EC50 of the model pheromone–PBP complex interacting with the receptor molecules is 6.8 μM, as compared with the EC50 = 1.5 μM of bombykol recently determined using heterologous expression. A possible mechanism widening the range of stimulus intensities covered by the dose–response curve of the receptor-potential is proposed

    Organizações sociais e agroecologia: construção de identidades e transformações sociais.

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    No presente trabalho, procuramos discutir as transformações ocorridas no espaço da agricultura familiar pós-Revolução Verde, especialmente a partir do movimento contestatório engendrado por organizações sociais que defendem o ideário agroecológico. Inicialmente, procurou-se compreender como a identidade a e realidade social são construídas e reconstruídas socialmente. Utilizou-se uma abordagem fenomenológica para investigar como se dá a ruptura com a realidade convencional e a transição para a agroecologia. Com base nas evidências empíricas, é possível dizer que a agroecologia participa da ressignificação positiva da identidade social dos agricultores. Entretanto, o reconhecimento da nova identidade passa pelo questionamento da realidade dominante a partir de crises vividas pelos agricultores. Sua manutenção requer partilhá-la intersubjetivamente com um grupo ou organização

    A social and ecological assessment of tropical land uses at multiple scales: the Sustainable amazon network

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    Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazônia Sustentável, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far

    Esquizofrenia: intervenção em Instituição Pública de Saúde

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    Os primeiros conceitos de esquizofrenia contemplavam definições inespecíficas sobre o transtorno esquizofrênico. Somente em 1980 Crow propôs a classificação mais conhecida para o transtorno: a dicotomização em subtipos I e II ou positivo/negativo, sendo os sintomas da síndrome positiva alucinações e delírios e da síndrome negativa, o embotamento afetivo e a pobreza do discurso. Embora a farmacoterapia tenha apresentado avanços no tratamento da doença, indica-se a psicoterapia para reverter os prejuízos sociais e interpessoais que ela acarreta. O objetivo deste estudo é relatar uma intervenção comportamental, em um Centro de Atenção Psicossocial, em paciente de 19 anos com emprego de Treinamento de Habilidades Sociais (THS) como uma possibilidade para o tratamento da esquizofrenia. Tal procedimento contribuiu para diminuir para a jovem o estereótipo da doença, visto que ampliou o seu repertório social e possibilitou avanços nas esferas psicológicas, sociais e vocacionais
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